Efecto de la aplicación de eCG antes o después de la IATF sobre la tasa de preñez en vacas holstein mestizas en la provincia de Pastaza

Abstract

The objective of the investigation, was determine the influence exerted by equine chorionic gonadotropin (eCG) on the size of the pre ovulatory follicle (FPO) and corpus luteum (CL day 7 and day 20) in 100 dairy cows Holstein in Pastaza. The application of the eCG was performed with four treatments. Within a conventional protocol of IATF. Treatments: TA= DIB+ BE + PG; TB= TA+ eCG day 8; TC= TA + eCG day 14 y TD= TA + eCG day 8 + eCG day 14). We used 100 holstein cows multiparous in postpartum period between 60 to 150 days, 2.25-2.75 of body condition; the feeding system was based on grazing pasture (Axonopus scoparius). Statistical analysis was performed by a General Mixed Linear Model test, using the Proc gen mod procedure of SAS vw 9.4 (2013). The results we obtain was for TA Size FPO (15.86 mm) and TB (15.33 mm) there’s not significant differences in between treatments with eCG and with out eCG. (P>0.05). The size of CL7 in TC (19.23 mm) and TD (21.88 mm) they were the biggest CL at the time to retire of the DIB (P = 0,0118). At day 20 the CL at T4 had a diameter of 23.29 mm (P<0.01). The pregnancy rate was TA: 64.5%; TB: 47.5%; TC:45,0% y TD: 58.1%, (P>0.05). In the Amazon region the size of the FPO, CL and the pregnancy rate was not increased with the administration of eCG in the IATF.